Cognitive Behavioral Therapy for the Treatment of Seasonal Affective Disorder (SAD)

• Scores on the Structured Interview Guide for the Hamilton Depression Rating Scale—Seasonal Affective Disorder Version [ Time Frame: Post-treatment ] [ Designated as safety issue: No ]
  The Structured Interview Guide for the Hamilton Depression Rating Scale—Seasonal Affective Disorder Version (SIGH-SAD) measures depressive symptoms on a continuous scale. Higher scores indicate worse outcome. Range of scores is 0 to 73. Generally, a score of 20 or higher is the cutoff for clinical depression.
  
  
• Remission Status on Structured Interview Guide for the Hamilton Depression Rating Scale—Seasonal Affective Disorder Version (SIGH-SAD) [ Time Frame: Post-treatment ] [ Designated as safety issue: No ]
  Dichotomous Remission Status (remitted or not) at post-treatment
  
  

SAD is a condition in which people experience depression as a result of seasonal variations in sunlight. Although light therapy is a common treatment for SAD, a large proportion of people with SAD are resistant to this treatment. CBT is effective for nonseasonal depressive disorders, but its use for SAD has not been thoroughly explored. This study will determine whether CBT, alone and combined with light therapy, is as effective as light therapy alone in reducing SAD symptoms.

Participants in this study will be randomly assigned to light therapy, CBT, a combination of light therapy and CBT, or a control group (no therapy) for 6 weeks. CBT will be conducted twice a week; light therapy will be conducted twice a day. Assessments will be made before, during, and after the study treatment. Depression scales, questionnaires, and behavioral tasks will be used to assess the depressive symptoms of participants. A 6-month and 1-year follow-up visit will also be conducted. During the follow-up visits, participants will be interviewed and will complete a questionnaire and a survey.